I gather that the Nobel Prize does not convey a tendency for honesty.

"[Machado] claimed her party's candidate, Mr Gonzalez, won by a landslide and Ms Machado said she could prove this because she had receipts from more than 80% of polling stations."

Yes, the opposition claimed that it had proof. However, it has not allowed any independent third parties to verify said proof. That she won a peace prize is inconsequential. They gave one to Henry Kissinger too.

None of it is proof, but all of it is evidence. Given that you have provided zero evidence to the contrary, the balance of evidence seems clear.